Caltrans says Bay Bridge bolt problem fixed

kgo

By ABC7

Spokesman Andrew Gordon said the work was completed at about 11
a.m. Wednesday and cost about $25 million, which is about twice the amount that
transportation officials predicted when the bolt problem was discovered in
the spring.

Gordon said the cost was higher than originally expected because,
"This was a unique, complex problem that demanded a unique, complex
solution."

In March, nearly one-third of the 96 bolts that secure earthquake
shock absorbers known as shear keys to the deck of the bridge failed when
they were tightened.

The shear keys are designed to prevent swaying during an
earthquake, which is a key element in the construction of the $6.4 billion
span because the goal is to make it seismically safe since a portion of the
existing bridge failed in the 1989 Loma Prieta earthquake.

The problem threatened to delay the plan by transportation
officials to open the new eastern span, which is intended to be safer in
earthquakes than the old span, over Labor Day weekend.

But transportation officials then learned of and approved a
short-term fix which involved inserting large steel plates, known as shims,
into each of four bearings, enhancing their ability to safely distribute
energy during an earthquake.

The long-term solution to fixing the broken bolts on the eastern
span was to cover them with an exterior saddle and cable system that is
encased in concrete.

Gordon said the temporary shims were removed Wednesday.

Several engineering experts have expressed concern that there
could be problems over the long term with other bolts on the new eastern span
but Gordon said tests are being conducted to address those concerns and see
if those bolts must be replaced at some point.

He said those tests are expected to be completed by next fall.
But Gordon said Caltrans officials believe that the new eastern
span is safe.